Draft gear



ct. 3o, 192s. f

w. H. coTToN DRAFT GEAR "Filed May 51, 1924 2 sheets-sheet 1 W. H.COTTON DRAFT GEAR Filed May 31, 1924 2 Sheets-SheetA 2 Ik montar:

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Patented Oct. 30, 1928.

UNITED STATES PATENT OFFICE.

WALTER H.v COTTON, 0F CHICAGO, ILLINOIS, ASSIGNOR TO UNION DRAFT GEARCOM- PANY, OF CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE.

DRAFT GEAR.

Application filed 'May 31,

rlhe invention relates to draft gears of the friction type used inconnection with railway cars, and particularly adapted for freightservice. The purposes of the invention are to secure simplicity ofconstruction, ease of assembly, smoothness of action, and highefficiency.

A preferred embodiment of the invention is hereinafter described, and isillustrated in the accompanying drawings, in which Fig. 1 is a. centralplan section through the gear, associated parts of the car being shownin detail;

Fig. 2 is a sectional view of the gear on the line 2-2 of Fig. l;

Fig. 3 is a plan section of the gear taken above the friction wedge andspring elements, associated parts of the car being shown in detail;

Fig. 4 is a view in perspective of one of the wedging elements; f

Fig. 5 is a view in perspective of one of a pair of wedging elements;and

Figs. 6 and 7 are views in perspective of friction plates embodied inthe gear.

Figs. 5, 6 and 7 are drawn to a scale about one-half of Vthat followedin the other figures.

The drawings represent the gear as applied to a car, Fig. 1 showing itin release position and Fig. 3 under compression in buff.

A pair of center or draft sills is represented at 10; the draft lugsassociated with the sills at 11, 11; the builing lugs at 12, 12; thecoupler butt at 13; and a yoke or coupler extension for encircling thegear .at 14. These elements form no part of the invention, and may be ofany desired form of construction.

The gear comprises a chambered follower 15, which, as shown, isassociated with the buffing lugs, and a-plate follower 16 shown asassociated with the draft lugs. The gear,

"il however, will operate in precisely the same manner if reversed. Theside, top and bottom walls of the chambered follower' are of Such lengththat they will make contact with the plate follower when the gear iscompressed to the desired limit. The side walls 17 flare slightly. Thetop and bottom walls 18, 19, may be parallel, as shown.

Within the chambered follower are anchored two sets of friction plates20, 21, preferably held in place by a pin 22 extend- 1924. Serial No.716,875.

ing through the side walls 17 and held in place by any suitable means,cotter pins being shown for thispurpose. The plates 20, 21, are all ofuniform thickness throughout and are preferably of such length that theyabut normally against the end wall of the follower 15 and terminate atthe' outer ends of its side walls. The width ofthe plates is such thatthey fit loosely between the top and bottom walls of the follower.

Two sets of similar friction plates 23, 24, interit or intercalate withthe two sets of plates 20, 21, and are approximately of the samedimensions as the latter except that they are preferably slightlyshorter. lVhen the gear. is in release position the plates 23, 24,project beyond the open end of the chambered follower, as shown in Fig.1, and when under full compression these plates extend approximately tothe end wallfof the follower, their outer ends being in the plane of theouter ends of the side walls. By designing these plates as of slightlyless length than the chambered follower the danger that any of them willexceed that length, due to inaccuracies in manufacture, is avoided.

The cooperating sets of plates 20, 23, and 21, 24, constitute two groupslocated, respectively, on opposite sides of the axis of the gear, theouter plate of each group being in contact with the side walls of thechamber of the follower. In arranging` the groups one of the slidingplates 23, 24, is in engagement with the follower' walls, the innerplate of each group being one of the anchored plates 20, 21.

Inter-posed between the two groups of frictionv plates are a pair ofwedging` shoes 25, 26, of the formshown in Fig. 5. Each of these shoescomprises body portions 27, 28, having outer flat surfaces for bearingagainst the friction plate, these body portions being united by the webs29, 30. The web 29, located approximately midway between the ends of theshoes, is formed with a wedging face 31. The inner faces of the bodyportions 27, 28, of the shoes are concave to provide space for thespring1 elements, and at the outer ends of these body portions areprovided walls 32, 33 which serve as spring seats.

A central wedging element 34 is interposed between the outer endportions of the shoes 25, 26, and interfits between the body portions27, 28, of each, and cooperates with the wedging faces 31 and with theplate follower 16.

Four helical springs 35, 36, 37, 38, ii-t one within the cavity of eachof the body pors tions of the two shoes 25, 267 and neat against the endwalls, as 32, 33, and the end wall of the chambered follower. A pin 39extends transveraely through the two groups of friction plates and islocated between the shoe webs 2l?, 30. The perforations 40Y in theanchored plates, as 20, which accommodate the retaining pin 22, take theform of slots, to provide clearance and permit the movement of the pin39. The movable or floating plates 23, 24, are slotted from their innerends, as shown at 41, to. receive the pin 39, which is engaged by theinner ends of the slots, and to permit these plates to be moved inwardlywithout interference by the pin 22. Channels 42 are formed in the sidewalls ofthe chambered follower to permit the free inward movement of thepin 39 as it is urged forward by the platesl 23, 24.

In assembling the gear the two sets of plates 20, 21, are arranged inapproximately the relation they are finally to assume, the shoes areplaced between the two sets, the pin 39 inserted, and the severalsprings are placed within the shoe cavities. The parts thus grouped maybe introduced into the chambered follower and the. pin 22 inserted. Themovable plates 23, 24, may now be individually placed and moved inwardlyuntil they make contact with the pin 39, and the wedge element 34 may beinserted in proper relation with the shoes.

When t-he gear is in release the several parts occupy the position asshown in Fig. 1, the outer ends of the floating plates projecting alittle beyond the outer ends of the shoes but terminating a little shortof the plate follower, the inner ends of their slots 41 engaging the pin39'.

In buff, the follower 16 is forced inwardly by the coupler 13, carryingwith it the wedge element 34 which tends to spread and advance the shoes25,y 26, coinpressing the two groups of friction plates. The follower 16presently comes into engagement with the floating plates 23, 2.4, andcarries them along with it, their advance, however, being resisted bythe gradually augmenting friction. The pin 39 is carried forwardly bythe floating plates. Ther shoes 25, 26, are advanced not only by theinward movement of' the wedging element 34, but also by the wedgingaction of the tapering side walls of the chambered follower which movesthem toward thc axis of the gear and causes their wedging faces toslide` inwardly on the cooperating faces of the element 34. rliheadvance of the shoes is resisted by the several springs which are putunder a high degree of compression.

Whenthe compressive force is relieved the various parts of the gear arerestored to their normal relation. The shoes are first moved backwardly,carrying with them the wedgging element 34 and reduc-ing the lateralpressure uponA the friction plates. When the pin 39 is encountered bythe web 30, it is moved baclwardly and with it the floating frictionplates.

The relative movement of the parts of the gear is the same in draft asinbufling.

I claim as my invention Y y 1. In a draft gear, in combination, achambered follower having flaring side walls, two sets of frictionplates anchored within the casing and parallel, respectively, withits'side walls and of approximately the same length as said follower,twoV sets of fioating` friction plates intercalat'ed with the plates ofthe first-named setsV and approximately of the same length as saidfirst-named plates, wedge lelements located between the two groups ofintercalated plates, springs opposing the movement. of the wedgeelements into the chambered follower, and an opposed follower engageablewith the floating friction plates and wedge elements. y

2. In a. draft gear, in combination, a chambered follower having flaringside walls, two sets of friction plates anchored within the casing andparallel, respectively, with its side walls,y two sets of floatingfriction plates intercalated with the plates of the first-named sets,said plates being approximately the length of said first named plates,wedge elements. located between the two groups of intercalated plates,springs'op-posing the movement of the wedge` elements into. thechambered follower' for creating friction between said plates throughouttheir length during compression of the gear, an opposed followerengageable with the floating friction plates and wedge elements, andmeans associated with the wedging elements for urging the floatingfriction plates to normal position.

3. In a draft `gear, in combination, a chambered follower having flaringside walls, an opposed follower, two sets of friction plates anchoredwithin the chambered follower and on opposite sides ofv its axis,

-two sets. of floating friction plates inter calated with the anchoredplates, co-operating wedge elements interposed. between the two groupsof plates and engageable by the opposed follower, means forinterlocking` the wedge elements with certain of the friction plates onthe. release of the gear, said means having a lost motion connectionwith said wedging elements and plates,l and spring means opposing thelongitudinal advance of the wedge elements.

4. In a draft gear, in combination, a chambered follower having flaringside walls, two

groups of intercalating friction plates, one set of plates of each groupbeing anchored within the chambered follower and extending`approximately the'length of the casing, the other set of each groupbeing longitudinally movable with reference to such follower, a plate ofeach of the last-named sets bearing against a side wall of the follower,and a plate of each of the anchored sets being the inner plate of thegroup, shoes slidably engaging the inner plates of the two groups, suchshoes having wedgingl faces, a central wedge interposed between the twoshoes, a follower for advancingvsuch wedge and engageable with the endsof the unanchored plates for advancing them, and spring means reactingbetween the end wall of the chambered follower and the shoes, said meanscomprising a plurality of individual spring elements at each side of thelongitudinal center line of the gear.

5. In a draft gear, in combination, a chambered follower having flaringside walls, two sets of friction plates within the follower andparallel, respectively, with its fiaring walls, a retaining pinextending through such plates and the follower walls, two sets offioating friction plates intercalated with the first-named sets ofplates, a pair of friction shoes interposed between the two groups ofplates and having wedging faces, a central wedge interposed between theshoes, a follower for advancing such wedge, spring means resisting theadvance of the shoes into the chambered follower, and a pin passingloosely through slots in all of the plates and the shoes and engageableby forwardly facing shoulders on the floating. plates and backwardlyfacing shoulders on the shoes.

6. In a draft gear, in combination, a charnbered follower' having a pairof opposite side walls flaring substantially the full length thereof, aplurality of elements acting together as a compressible wedge engageablewith such walls, an opposed follower for urging such wedge into thechambered follower, and spring means opposing the action of the lastnamed follower, said means comprising independent resilient units ateach side of the longitudinal center line of said gear.

7. In a draft gear, in combination, a chambered follower, a pair offriction shoes movable into such follower and having spring seats attheir outer ends, springs interposed between such seats and thetransverse wall of the follower at each side of the longitudinal centerline of the gear, wedge means for spreading and advancing the shoes, asecond follower engageable with such means, and means including elementsin frictional engagement with said chainbered follower for frictionallyengaging the shoes and causing their relative approach as they advance.

8. In a draft gear, in combination, al chambered follower having flaringwalls, two sets of friction plates anchored to such follower, two setsof iioating friction plates intercalated with the anchored plates andthe side walls of the follower and normally projecting beyond thelatter, a pair of wedging friction shoes interposed between thefirstnamed sets of plates, means for connecting said floating plates tosaid shoes, said means having a lost motion connection with said shoes,spring means reacting between the end wall of the followerI and one ofsaid shoes, spring means reacting between the end wall of said followerand the other of said shoes independently of said first-named means, acentral wedge cooperating with the wedge faces of the shoes, and asill-engaging follower engaging the central wedge and the exposed endsof the floating plates.

9. In a draft gear, a chamber-ed follower having a flaring wall, a groupof intercalated friction plates frictionally engaging lsaid wall, agroup of intercalated friction plates engaging' the wall of saidfollower opposite said fiaring wall, means including separate resilientmembers located at opposite sides of the longitudinal center line of'the gear and between said groups of plates for forcing said plates intofrictional engagement with said walls and with one another duringcompression of said gear.

WALTER H. COTTON.

